According to the suit, Bresnahan called in an order for a “Billy Club unwich." The meal (which doesn’t included bread and is instead wrapped in lettuce) usually consists of roast beef, smoked ham, provolone cheese, Dijon mustard, lettuce, tomato and mayonnaise.

Bresnahan claimed that she specifically asked that the restaurant not include the mustard and mayonnaise. But when she bit into the meal she quickly realized that both condiments were incorporated anyway. Bresnahan says that she started to notice an adverse reaction to ingredients in Dijon mustard about a year before the incident and has been avoiding the condiment ever since.

Wolf Mueller, Bresnahan's attorney, said his client was forced to spend months dealing with the reaction, with no noticeable improvement. She also had to move from her apartment and can’t work since she can barely "speak above a whisper." Mueller told the Washington Post that it is unclear if the damage to Bresnahan's mouth is permanent.

“It is not unreasonable to expect a sandwich shop to make the sandwich according to the order,” Mueller explained to the paper via e-mail. “Sometimes no harm results, other than annoyance. Other times, like here, serious harm can result. Either way, Jimmy John’s is accountable for its negligence.”

According to the FDA, food allergies send about 30,000 Americans to the emergency room annually and an estimated 150 to 200 people die each year because of allergic reactions to food.

The incident comes amid a string of recent lawsuits in which restaurants have been sued for serving food items that triggered customers' allergies.